Rear drive acceptable spline wear

[brider]

Finally pulled the rear drive and swingarm off my Cal 2 @ 45k miles, and yes, this was the first time.

Suprisingly, there was no rust anywhere in the bearings or splines, with vestiges of functional grease/oil still on all surfaces.

But the pinion input splines WERE worn, as were the mating splines on the driveshaft coupler. The splines on the driveshaft-side of the coupler and the driveshaft itself looked good.

The pinion-spline wear did not look so severe as some pics I've seen posted here, and my first thought was to get a replacement coupler, which would eliminate half the slop at the coupler-pinion interface, and call it good.

It's an Automatic.....I should be OK, no?

Swingarm bearings themselves feel notchy, but the pressed-in races in the swingarm look good; I can't tell by looking just how you'd remove the drive-side race, it looks tight up against the u-joint tube?

Carrier bearing DEFINITELY felt bad, but no evidence of driveshaft spinning in race, or outer race spinning in swingarm, guess I caught it in time!

[bigbikerrick]

can you post a picture of the splines?
Rick

[rodekyll]

I'd try to extend the life of the other more expensive bits with a new coupler and then ride with no unnecessary clutching.  Maybe even new grease if you've got some.  The Cal II auto drive shaft is hard to come by.

You use a blind race puller to remove the old pivot bearing races.  It's a slide hammer that hooks the race from behind.  I've dremmeled them and broken them out with a chisel, too.

How does the u-joint feel?

[brider]

I'll look at the swingarm races in the daylight today, but I thought there was no room behind them to get puller jaws? (that would be a bad design).

U-joint looked very good, no discernible play. I will post pics later today.

[pehayes]

I'll look at the swingarm races in the daylight today, but I thought there was no room behind them to get puller jaws? (that would be a bad design).

You need a blind bearing puller with a lip, not with jaws.



Also possible to pack the center with grease.  Use a snug fitting puch to hit the grease.  Hydraulic force pushes or squishes out the bearing or race.

Patrick Hayes
Fremont CA

[brider]

Here's the rear drive input and coupler splines:





Here's the driveshaft end of the coupler, the driveshaft splines are the same condition. U-joint has no play:

[rodekyll]

That's a mess, right there.  The pinion splines appear to be trashed.  Drive shaft might have some life left.  Is the a ridge in the middle of the coupler bore?

Your deep problem might be the rear wheel cush bits are seized or the rubbers have gotten hard.  Take that stuff apart and service/replace.

[jacksonracingcomau]

I spent 20 years chasing this issue
The resolve for me, found and fixed by genius engineer I met
Problem. Flange for drive box not square to uj bearing mount
Fix
Make mandrel to mount in uj bearing, we used a broken uj with solid bar mounted in it, dial gauge at end. Mill flange square with zero runout.
Mine was .100" out, now true
Had many chew splines over the years but never really understood problem

When square you can weld coupling to pinion, will now get rest  of life out of pinion

Previous to this we had welded coupling to pinion but always broke weld after 10k odd miles

Has now been 25k, problem fixed, no wear on splines whatsoever
Some swingingarms are square some are not, worn splines and uj spinning in bearing are the clues
Hope this helps, had me going mad for very long time, resistance is imperceptible turning pinion but actually shaft is doing the chubby checker.

[Idontwantapickle]

This /\

Until the alignment is resolved the problems will return.

[John A]

I made a jig out of 1/2" plate that I squarely mounted blocks to that are threaded for swingarm pivots that I use for trueing up swingarms after modifying them for wider tires and extra bracing. I'm of the opinion that the flange is not strong enough for really hard use, like a sidecar. I don't think I ever checked a flange for being true before I modified it, and it makes sense to me that some of them would be out from the factory. Good tip!

[5154guzzi]

Brider,  I couldn't get my swingarm bearing races to budge with my blind bearing puller, even after soaking and heat.  Another way besides chiseling, or using a small cutoff wheel, is to make a plug out of steel, tap threads through the center and weld it into the race.  Then run a appropriate length bolt through the plug, when it contacts the swingarm body it will act as a puller.  On the non ujoint side, I placed a piece of solid steel rod, cut to fit into the pivot tube for the bolt to push against.

 

 

[brider]

The pinion splines appear to be trashed.  Drive shaft might have some life left.  Is the a ridge in the middle of the coupler bore?

Yes, there is a ridge at the mid-point of the coupler, I wasn't sure if it was a machined feature or not. Driveshaft splines look almost perfect to my naked eye, why the "might" in your assessment?

Jacksonracingcomau brings up the point about rear drive flange/carrier bearing centerline being out of tolerance (should be theoretical perfect 90 deg?), is this the effect of that? The pinion splines wear, but NOT the driveshaft splines? I would think a mis-alignment would distribute wear evenly between the 2 (assuming the same material and temper)?

[rodekyll]

I'm looking at tiny pictures on my phone.  "Might" is because I can't see them clearly.

The ridge in the coupler is wear.

[jacksonracingcomau]

Yes, there is a ridge at the mid-point of the coupler, I wasn't sure if it was a machined feature or not. Driveshaft splines look almost perfect to my naked eye, why the "might" in your assessment?

Jacksonracingcomau brings up the point about rear drive flange/carrier bearing centerline being out of tolerance (should be theoretical perfect 90 deg?), is this the effect of that? The pinion splines wear, but NOT the driveshaft splines? I would think a mis-alignment would distribute wear evenly between the 2 (assuming the same material and temper)?

On "normal" uj/ shaft/coupling/pinion ie 4 splines to wear
I have worn all at different times, actually broke a drive shaft once
I believe your shaft is like original convert, one piece uj and drive shaft, no top spline to wear
The load is now all at rear end, pinoion/coupling.
Shaft/coupling far less loaded but would eventually wear if you want to push it that far
Please mount a dial gauge to fixed shaft in bearing, flange must be completely parallel to bearing mount. If it is not, problem can only continue.
Your uj /shaft actually easy to mount gauge to, as long as tight in bearing, will read square or not
If bearing worn, replace it first, obviously

[bigbikerrick]

Jacksonracing, can you please explain how a "shade tree mechanic" can check the swing arm flange for trueness,Including what tools are needed?  Also please explain how it is corrected, if found to be off.I would like to check the one on my Cal II automatic, and am not sure I understand the procedure completely.
Thanks
Rick.

[brider]

Jacksonracing, can you please explain how a "shade tree mechanic" can check the swing arm flange for trueness,Including what tools are needed?

True that! I'm pretty clear on what the issue is Jackson is trying to investigate, but I, too can't get a mental image of how to set up a dial guage to measure.

To beat a dead horse more thoroughly: Yes, mine is a 1-piece UJ/shaft, with splines on the female end of the UJ at the front, and male splines on the aft end. If the load is all at the rear end as Jackson opines, the load at the shaft/coupling HAS to equal the load at the coupling/pinion interface, simple physics. I guess it doesn't matter WHY the driveshaft/coupling didn't wear, it just bugs me, but I should be happy the shaft is OK.

Wait......I know why.....the aft end of the shaft is ~7 inches from it's "fixed" carrier bearing support, and with whatever tolerance there is at that interface, it allows the aft end to "float", and drive the mis-alignment into the pinion, which has virtually zero "float" capability, as long as the pinion bearings are still tight. That's my theory, anyway.

Back to Jackson's suggested fix:

Make mandrel to mount in uj bearing, we used a broken uj with solid bar mounted in it, dial gauge at end. Mill flange square with zero runout.
Mine was .100" out, now true

When square you can weld coupling to pinion, will now get rest  of life out of pinion

I find it VERY hard to believe there was a tenth of an inch runout at the pinion compared to the carrier centerline, but I'm not disputing there WAS/IS significant runout. But milling the flange of the swingarm such a specialized amount is WAAAAAY beyond my ability to even convey to a machine shop, even if I WAS able to measure and quantify the mis-alignment.

I am stumped right now on how to proceed. Ultimately, the failure mode looks like completely stripped pinion splines if I were to ride it as-is, but I'd bet I could prolong that many years at my present pace if I replace the coupler to reduce the slop by 50% at that interface. I know that will make most of the mechanical purists cringe.

[John A]

the way I true up the flange is I put the drive box on and use a machinist's square on the axel and drive flange for the wheel, also to the floor of my jig. I can see how that's only half of trueing it, I hadn't thought of making it true to the ujoint carrier bearing. when I straighten it, I would heat it and move it that way. in the future I will make a fixture to check the flange for square to the driveshaft, I would hesitate to thin the flange for strength considerations as I've not came up with an elegant solution to strengthening that, but I will.

[jacksonracingcomau]

True that! I'm pretty clear on what the issue is Jackson is trying to investigate, but I, too can't get a mental image of how to set up a dial guage to measure.

To beat a dead horse more thoroughly: Yes, mine is a 1-piece UJ/shaft, with splines on the female end of the UJ at the front, and male splines on the aft end. If the load is all at the rear end as Jackson opines, the load at the shaft/coupling HAS to equal the load at the coupling/pinion interface, simple physics. I guess it doesn't matter WHY the driveshaft/coupling didn't wear, it just bugs me, but I should be happy the shaft is OK.

Wait......I know why.....the aft end of the shaft is ~7 inches from it's "fixed" carrier bearing support, and with whatever tolerance there is at that interface, it allows the aft end to "float", and drive the mis-alignment into the pinion, which has virtually zero "float" capability, as long as the pinion bearings are still tight. That's my theory, anyway.

Back to Jackson's suggested fix:

I find it VERY hard to believe there was a tenth of an inch runout at the pinion compared to the carrier centerline, but I'm not disputing there WAS/IS significant runout. But milling the flange of the swingarm such a specialized amount is WAAAAAY beyond my ability to even convey to a machine shop, even if I WAS able to measure and quantify the mis-alignment.

I am stumped right now on how to proceed. Ultimately, the failure mode looks like completely stripped pinion splines if I were to ride it as-is, but I'd bet I could prolong that many years at my present pace if I replace the coupler to reduce the slop by 50% at that interface. I know that will make most of the mechanical purists cringe.

Think you're thinking while typing but you are getting it
.100" was at end of flange not middle of pinion, one side against other ie pissed as rat
Flange face  parallel to uj bearing is what you want
Not simple, you need a mill, up to you wether it's worth it
Then weld new coupler to worn pinion splines
Am flying home tomorrow, will try explain more in a few days, takes 3 days to come good after flying east 12k miles

[brider]

... one side against other ie pissed as rat

What him say? (anybody remember that cartoon?!) "...pissed as rat...?

No need to clarify, I get what you're talking about. I am not prepared to do the right thing, I'm going to find the best spline lube I can (look for a new thread if you're interested), do a diligent search for a used coupler that's in better shape than mine, and when the time comes that the swingarm is holding me up from riding, I'm putting it back together. I know what it feels like when an Automatic stops forward motion under power.

[Antietam Classic Cycle]

.100" is 2.54 mm. How would the axle even go in if the flange was off that much? The rear drive would be visibly cocked at an angle, no dial gauge needed. What am I missing here?

[rjamesohio]

FWIW I’ve removed internal races in the past by welding a bead around them; the heat causes them to shrink and they generally fall right out


Sent from my iPhone using Tapatalk Pro

[bigbikerrick]

Are the driveshaft couplers for the automatic bikes no longer available new?
Rick.

[brider]

I can't find the couplers no-wheres, I called Harper's and he/they said they were scrounging for a different customer for one and couldn't find any.

[brider]

One laast thought:

I will admit I was negligent in servicing my rear drive, so when it leaves me stranded that's on me.

But he good thing is that the Automatic eliminates the "slamming" of splines, because it's always acting like the clutch is dragging, keeping the worn faces in contact (except on deleleration). I feel better now, and may even go lighter on the throttle from stops.

[Antietam Classic Cycle]

I can't find the couplers no-wheres, I called Harper's and he/they said they were scrounging for a different customer for one and couldn't find any.

How much do you want to spend?
https://www.ebay.com/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=18327700&_sacat=6000

[Chuck in Indiana]

How much do you want to spend?
https://www.ebay.com/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=18327700&_sacat=6000

  At those prices, a guy could tool up and make some..

[rodekyll]

I saw that coming and had a convert pinion resplined for the 5-speed coupler.  Now I can put the 20-spline forward yolk on a 5-speed u-joint and use a 5-speed drive shaft.  A guy in WA welded a 5-speed coupler to his stripped convert splines to do the same thing.

[brider]

How much do you want to spend?
https://www.ebay.com/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=18327700&_sacat=6000

Thanks, I obviously did not search using the correct buzzwords.

Chuck: Could you REALLY make this part to the correct dimensions for less than a buck and a half? I mean, if you have the machine tools and raw stock and skill, then more power to you, brother, but I almost didn't click on the link 'cause I thought the price was a LOT higher. Guys spend more on gadgets and tank bags than that.

You should at least temper that post with your signature  <snapping suspenders> qualifier.

[brider]

  A guy in WA welded a 5-speed coupler to his stripped convert splines to do the same thing.

Regarding welding, which has been mentioned before in this thread: Do you know of anyone who has done this and gotten extended life out of the weld? If the drive-attach flange is indeed skewed to the centerline of the driveshaft, I can easily imagine the welded coupler now trying to create a bending moment with the driveshaft, or worse, the coupler welded non-concentric or skewed itself, and wobbling as it spins. Is it an easy task to weld the couple centered within acceptable spec, or should this be tooled up, also?

The price for the coupler seems reasonable to me to eliminate ~ 50% of the slop, but if welding is easy and permanent, why not try that?

[rodekyll]

I don't know how it worked out for him.  I had the same concern.